GLORIA

GEOMAR Library Ocean Research Information Access

X

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • American Astronomical Society  (6)
  • 2020-2024  (6)
Material
Publisher
  • American Astronomical Society  (6)
Person/Organisation
Language
Years
  • 2020-2024  (6)
Year
Subjects(RVK)
  • 1
    Online Resource
    Online Resource
    GECAM Detection of a Bright Type I X-Ray Burst from 4U 0614+09: Hint for Its Spin Frequency at 413 Hz
    American Astronomical Society ; 2022
    In:  The Astrophysical Journal Vol. 935, No. 1 ( 2022-08-01), p. 10-
    Details
    In: The Astrophysical Journal, American Astronomical Society, Vol. 935, No. 1 ( 2022-08-01), p. 10-
    Abstract: One month after launching the Gravitational Wave High-energy Electromagnetic Counterpart All-sky Monitor, a bright thermonuclear X-ray burst from 4U 0614+09 was observed on 2021 January 24. We report the time-resolved spectroscopy of the burst and a hint of burst oscillation at 413 Hz with a fractional amplitude ∼2.0% (rms). This coincides with the burst oscillation previously discovered with Swift/Burst Alert Telescope (Strohmayer et al. 2008), and therefore supports the spin frequency of this source. This burst is a bright one in the normal bursts detected from 4U 0614+09, which leads to an upper limit of distance estimation of 3.1 kpc. The folded light curve during the burst oscillation shows a sinusoidal structure, which is consistent with previous observations.
    Type of Medium: Online Resource
    ISSN: 0004-637X , 1538-4357
    URL: Article
    DOI: 10.3847/1538-4357/ac7ff8
    RVK:
    UA 1000
    Language: Unknown
    Publisher: American Astronomical Society
    Publication Date: 2022
    detail.hit.zdb_id: 2207648-7
    detail.hit.zdb_id: 1473835-1
    SSG: 16,12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 2
    Online Resource
    Online Resource
    GECAM Localization of High-energy Transients and the Systematic Error
    American Astronomical Society ; 2023
    In:  The Astrophysical Journal Supplement Series Vol. 265, No. 1 ( 2023-03-01), p. 17-
    Details
    In: The Astrophysical Journal Supplement Series, American Astronomical Society, Vol. 265, No. 1 ( 2023-03-01), p. 17-
    Abstract: The Gravitational Wave High-energy Electromagnetic Counterpart All-sky Monitor (GECAM) is a pair of microsatellites (i.e., GECAM-A and GECAM-B) dedicated to monitoring gamma-ray transients including the high-energy electromagnetic counterparts of gravitational waves, such as gamma-ray bursts, soft gamma-ray repeaters, solar flares, and terrestrial gamma-ray flashes. Since launch in 2020 December, GECAM-B has detected hundreds of astronomical and terrestrial events. For these bursts, localization is the key for burst identification and classification as well as follow-up observations in multiple wavelengths. Here, we propose a Bayesian localization method with Poisson data with Gaussian background profile likelihood to localize GECAM bursts based on the distribution of burst counts in detectors with different orientations. We demonstrate that this method can work well for all kinds of bursts, especially extremely short ones. In addition, we propose a new method to estimate the systematic error of localization based on a confidence level test, which can overcome some problems of the existing method in the literature. We validate this method by Monte Carlo simulations, and then apply it to a burst sample with accurate location and find that the mean value of the systematic error of GECAM-B localization is ∼2.°5. By considering this systematic error, we can obtain a reliable localization probability map for GECAM bursts. Our methods can be applied to other gamma-ray monitors.
    Type of Medium: Online Resource
    ISSN: 0067-0049 , 1538-4365
    URL: Article
    DOI: 10.3847/1538-4365/acafeb
    RVK:
    UA 1000
    Language: Unknown
    Publisher: American Astronomical Society
    Publication Date: 2023
    detail.hit.zdb_id: 2006860-8
    detail.hit.zdb_id: 2207650-5
    SSG: 16,12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 3
    Online Resource
    Online Resource
    Chemically Fresh Gas Inflows Detected in a Nearby High-mass Star-forming Region
    American Astronomical Society ; 2021
    In:  The Astrophysical Journal Letters Vol. 923, No. 1 ( 2021-12-01), p. L20-
    Details
    In: The Astrophysical Journal Letters, American Astronomical Society, Vol. 923, No. 1 ( 2021-12-01), p. L20-
    Abstract: We report the detection of a chemically fresh inflow that is feeding high-mass young-stellar-object (HMYSO) growth in the nearby high-mass star-forming region G352.63 made with both the Atacama Large Millimeter/submillimeter Array (ALMA) and the Submillimeter Array (SMA). High-quality images of the dust and molecular lines from both ALMA and SMA have consistently revealed a gravitationally controlled cold (∼10 K) gas inflow of chemically fresh molecules (e.g., CCH and HC 3 N) toward the central HMYSO and its surrounding dense gas structure, which has a possible torus- or disk-like morphology. The HMYSO is also observed to have an outflow, which is nearly perpendicular to the torus and its parental filament, and thus can be clearly separated from the inflows. These kinematic features provide observational evidence to support the conjecture that the infalling streamers in high-mass star-forming regions could proceed in a similar process to that observed in low-mass counterparts. The chemically fresh infalling streamers could also be involved in the disk or torus configuration, fragmentation, and accretion bursts that occur in both simulations and observations.
    Type of Medium: Online Resource
    ISSN: 2041-8205 , 2041-8213
    URL: Article
    DOI: 10.3847/2041-8213/ac3ec8
    Language: Unknown
    Publisher: American Astronomical Society
    Publication Date: 2021
    detail.hit.zdb_id: 2207648-7
    detail.hit.zdb_id: 2006858-X
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 4
    Online Resource
    Online Resource
    Testing Blandford–Znajek Mechanism in Black Hole Hyperaccretion Flows for Long-duration Gamma-Ray Bursts
    American Astronomical Society ; 2021
    In:  The Astrophysical Journal Vol. 908, No. 2 ( 2021-02-01), p. 242-
    Details
    In: The Astrophysical Journal, American Astronomical Society, Vol. 908, No. 2 ( 2021-02-01), p. 242-
    Abstract: Long-duration gamma-ray bursts (GRBs) are generally related to the core-collapse of massive stars. In the collapsar scenario, a rotating stellar-mass black hole (BH) surrounded by a hyperaccretion disk has been considered as one of the plausible candidates of GRB central engines. In this paper, we work on a sample including 146 long GRBs with significant jet break features in the multiband afterglows. The jet opening angles can then be obtained by the jet break time. By assuming GRB jets powered by the Blandford–Znajek (BZ) mechanism in the BH hyperaccretion system, we analyze the distributions of the long GRB luminosities and durations in the samples, and constrain the accretion rates for the different BH spins. As a result, we find that the BZ mechanism is so powerful that it is possible to interpret the long GRB prompt emissions within reasonable accretion rates.
    Type of Medium: Online Resource
    ISSN: 0004-637X , 1538-4357
    URL: Article
    DOI: 10.3847/1538-4357/abd6bd
    RVK:
    UA 1000
    Language: Unknown
    Publisher: American Astronomical Society
    Publication Date: 2021
    detail.hit.zdb_id: 2207648-7
    detail.hit.zdb_id: 1473835-1
    SSG: 16,12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 5
    Online Resource
    Online Resource
    Statistical Analyses of the Energies of X-Ray Plateaus and Flares in Gamma-Ray Bursts
    American Astronomical Society ; 2022
    In:  The Astrophysical Journal Vol. 924, No. 2 ( 2022-01-01), p. 69-
    Details
    In: The Astrophysical Journal, American Astronomical Society, Vol. 924, No. 2 ( 2022-01-01), p. 69-
    Abstract: Distinct X-ray plateau and flare phases have been observed in the afterglows of gamma-ray bursts (GRBs), and most of them should be related to central engine activities. In this paper, we collect 174 GRBs with X-ray plateau phases and 106 GRBs with X-ray flares. There are 51 GRBs that overlap in the two selected samples. We analyze the distributions of the proportions of the plateau energy E plateau and the flare energy E flare relative to the isotropic prompt emission energy E γ ,iso . The results indicate that they well meet the Gaussian distributions and the medians of the logarithmic ratios are ∼−0.96 and −1.39 in the two cases. Moreover, strong positive correlations between E plateau (or E flare ) and E γ ,iso with slopes of ∼0.95 (or ∼0.80) are presented. For the overlapping sample, the slope is ∼0.80. We argue that most of X-ray plateaus and flares might have the same physical origin but appear with different features because of the different circumstances and radiation mechanisms. We also test the applicabilities of two models, i.e., black holes surrounded by fractured hyperaccretion disks and millisecond magnetars, on the origins of X-ray plateaus and flares.
    Type of Medium: Online Resource
    ISSN: 0004-637X , 1538-4357
    URL: Article
    DOI: 10.3847/1538-4357/ac35e7
    RVK:
    UA 1000
    Language: Unknown
    Publisher: American Astronomical Society
    Publication Date: 2022
    detail.hit.zdb_id: 2207648-7
    detail.hit.zdb_id: 1473835-1
    SSG: 16,12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 6
    Online Resource
    Online Resource
    NEOWISE Variability of the New Gaia Herbig Ae/Be and Classical Be Stars—Variability Sample and Statistical Analysis
    American Astronomical Society ; 2023
    In:  The Astrophysical Journal Supplement Series Vol. 264, No. 2 ( 2023-02-01), p. 38-
    Details
    In: The Astrophysical Journal Supplement Series, American Astronomical Society, Vol. 264, No. 2 ( 2023-02-01), p. 38-
    Abstract: Light variability is an essential attribute of young stellar objects (YSOs) at the pre-main-sequence (PMS) stage, which can be treated as an indicator to trace star formation. We present a statistical study on the infrared NEOWISE variability of new and large-sized PMS stars as well as Herbig Ae/Be (HAeBe) and classical Be (CBe) stars identified from Gaia Data Release 2. A total of 3792 (including 714 HAeBe), 417, and 473 NEOWISE variable sources were detected from the catalog of 8470 PMS (including 1361 HAeBe), 693 CBe, and 1309 uncertain (possibly belonging to either HAeBe or CBe) stars, respectively. We found that 80% of the PMS variables are dominated by irregular infrared variability, whereas variables in the CBe and uncertain categories exhibit comparable contributions from secular (linear, curved, and periodic) and stochastic (burst, drop, and irregular) variables. This, in combination with infrared W1–W2 colors, W4 luminosities, and the spectral energy distribution slope at near- and mid-infrared wavelengths, suggests different evolutionary stages of the PMS (including HAeBe), uncertain, and CBe stars, from less to more evolved. A statistical analysis of variable source properties (e.g., period and fractional amplitude) further reveals a potential sequence possibly associated with disk evolution for different types of light curves (from linear, to curved, periodic, stochastic, and nonvariable stars). Possible mechanisms for the variable sources are suggested to be related to either extinction via circumstellar matter, or contribution of multiple systems surrounding the YSOs, as opposed to variable accretion (e.g., episodic accretion or accretion burst).
    Type of Medium: Online Resource
    ISSN: 0067-0049 , 1538-4365
    URL: Article
    DOI: 10.3847/1538-4365/aca53d
    RVK:
    UA 1000
    Language: Unknown
    Publisher: American Astronomical Society
    Publication Date: 2023
    detail.hit.zdb_id: 2006860-8
    detail.hit.zdb_id: 2207650-5
    SSG: 16,12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...